Volvo has announced it will test Formula 1-style KERS flywheel technology as a means to improving eco-efficiency in it road cars.
By using a flywheel to store energy that would otherwise be lost under braking Volvo hopes to cut fuel consumption by up to 20% while also increasing performance.
Volvo flywheel KERS: what’s that then?
KERS stands for Kinetic Energy Recovery System.
The flywheel version works by using brake energy to spin a flywheel – up to 60,000rpm in this instance – storing this energy where it would otherwise be lost. The energy can then be released to help the car accelerate again.
Similar systems have been tested by other carmakers – as well as used in Formula 1 and on the Porsche 911 GT3 R Hybrid racing car (which coincidentally achieved its first outright victory over the weekend) – but Volvo will be among the first to carry out extensive trials on public roads.
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What’s the difference?
Volvo’s flywheel is also different in two significant respects.
Firstly, it acts directly on the rear axle by means of a special compact transmission, while leaving a conventional combustion engine to drive the front wheels in a conventional manner.
The flywheel, meanwhile, is made from carbon fibre instead of steel – increasing rotational capacity while keeping down weight. Spinning in a vacuum to minimise frictional loses, the result is a device that’s roughly 20cm across and weighs around 6kg, yet promises big results.
What’s the benefit?
Flywheel KERS is really only suitable for storing energy for a short period of time – but this is good news for city centre and more spirited driving.
Frequent stopping and starting means energy is being stored and released at frequent intervals – and this process helps reduce fuel consumption. Volvo’s system will synchronise with shutting down the combustion engine under braking, saving even more fuel.
The energy released by the flywheel is also equivalent to an extra 80hp. This reduces the load on the combustion engine when accelerating – again improving fuel consumption – or helps the car respond faster. So much so Volvo reckons it will make a four-cylinder engine feel like a six-cylinder engine
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Lower cost, wider ranging solution
Further benefits include the relatively low cost of the technology – there are no expensive battery components here (which also add large amounts of weight) – and the ability to deploy it in a wider range of vehicles.
This includes smaller cars where there is no space for the additional batteries needed to create a more ordinary hybrid or plug-in hybrid variant – like the ultra efficient Volvo V70 plug-in hybrid that’s due to go on sale next year.
Testing of the Volvo flywheel KERS starts later this year, and Volvo is confident it will be able to bring it to market ‘within a few years’.
More power and more efficiency without a big increase in cost? Sounds almost too good to be true – here’s hoping Volvo’s trials prove successful.
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